IV infusion monitoring device

ABSTRACT

An IV infusion monitoring device is provided to measure and to display, during whole infusion process, the liquid level data including the weight of remaining medical liquid in an IV bottle, the liquid flow rate and the remaining time from the completion of an IV infusion process. It also gives alarm as the medical liquid in an IV bottle drops to a predetermined low level. The IV infusion monitoring system comprises an electric load sensor, a signal processor, a monitor terminal and a power provided preferably by a battery. The load sensor measures the weight of the medical liquid in the IV bottle. The measured signal is then transmitted to the signal processor for processing and generating the liquid level data, which are then sent to the monitor terminal for display. The monitor terminal can also generate an alarm if the liquid level drops to the predetermined value. Furthermore, the monitoring device combines with a server and a plurality of PDA devices to form a communication network so that a nurse can monitor the IV infusion process from a remote location.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional patent applicationNo. 61/338,636, filed on Feb. 22, 2010 by the present inventors to USPatent and Trademark Office.

REFERENCES CITED U.S. Patent Documents

3,656,478 Apr. 18, 1972 Swersey 604/66 3,939,360 Feb. 17, 1976 Jackson307/118 4,589,372 May 20, 1986 Smith 119/51.02 5,563,584 Oct. 8, 1996Rader et al. 340/618

FEDERALLY SPONSORED RESEARCH

Not applicable

SEQUENCE LIST OF PROGRAM

Not applicable

FIELD OF INVENTION

The present invention relates to a monitoring system of a liquid feedingline, and more particularly to an IV infusion monitoring device.

BACKGROUND OF THE INVENTION

Assume a patient lies on bed to receive IV infusion. There are two typesof infusion systems. One is by pump, another is by gravity. The pumpinfusion system is very costly and often encounters maintenance trouble.Therefore, many hospital workers prefer to use the traditional gravityinfusion system. The gravity IV infusion line consists of three parts:a) An IV bottle contains medical liquid and air above the medicalliquid; (b) Infusion line includes a liquid needle inserted inside theIV bottle to receive medical liquid, a plastic tube (liquid tube) withone end connected to the liquid needle as liquid inlet and another endconnected to the IV injection needle for injecting the medical liquidinto the patient vein. A flow rate switch is located in the middle ofthe plastic tube to control the flow rate manually; (c) Air lineincludes an air needle inserted into the IV bottle to apply air pressurefor driving the liquid flow, and a plastic tube (air tube) with one endconnected to the air tube as air outlet and another end opened to theenvironment as air inlet. As the medical liquid in the IV bottle dropsto a predetermined low level, i.e., nearly finished, the bottle must bereplaced by a new one, otherwise air may enter the infusion line andcauses serious medical problems.

So far, the job of bottle replacement needs frequent supervision frompatient and nurses by eyeball. This task becomes a heavy burden ofmedical workers, particularly at night. To develop an alarming systemfor IV infusion becomes a big demand from hospitals and patients.

Furthermore, the hospitals also wish to monitor whole IV infusionprocess for better care of the patients. For example, an IV infusionprocess may go wrong if a patient or particularly a baby moves violentlyduring infusion. In this case, monitoring whole infusion process, e.g.,the liquid level and the infusion speed at each time moment, becomesnecessary. Unfortunately, there is no any satisfied device existing inthe current market for this task. The present invention provides an IVinfusion monitoring device, which not only gives alarm when the IVbottle needs replacement, but also provides all IV infusion data duringwhole infusion process, e.g., the liquid level, the liquid flow rate andthe remaining time from the completion of the infusion process. Thepresent invention also includes a communication network, so that thenurses or other hospital workers can monitor the whole IV infusionprocess of each patient from either a close or a remote location throughthe network.

U.S. Pat. No. 3,656,478 to Swersey, discloses an infusion monitor whichis able to supply a medical liquid to a patient at either a high rate orlow rate, depending upon the weight of the patient. If the weight of thepatient decreases below a preset value, the infusion monitor is switchedto the high speed. If the weight of the patient returns to normal, theinfusion monitor switches back to the low speed. The present inventionis apparently different from the Swersey's. The present inventionmeasures and monitors the weight of the medical liquid in the IV bottle,and calculates the liquid flow rate during infusion.

U.S. Pat. No. 3,939,360 to Jackson discloses a liquid level sensor andelectrode assembly therefore. Jackson's disclosure applies threecapacitance plates to measure the capacitance which is related to theliquid level. The present invention applies weight measurement of themedical liquid in the IV bottle by an electric load sensor to monitorthe infusion process.

U.S. Pat. No. 4,589,372 to Smith discloses a dispensing system similarto the Swersey's. The Smith's system first determines the weight of ananimal subject, and then a delivery unit supplies a predetermined amountof material to the animal subject. The amount of supplied material is afunction of the weight of the subject. It is apparent that the presentinvention is completely different from the Smith's. The presentinvention monitors the weight of the remaining medical liquid in the IVbottle and the liquid flow rate during infusion, not the control of theinfusion speed as a function of the weight of the animal subject.

U.S. Pat. No. 5,563,584 to Rader et al. discloses a liquid level sensingand monitoring system for medical fluid infusion systems. Rader'sdisclosure applies pressure sensor technology. A pressure sensor isinserted into the outlet of a liquid container and contacts the liquidfor detecting the liquid level. The present invention applies the loadsensor for measuring the weight of the medical liquid in the IV bottleduring infusion.

The present invention provides an IV infusion monitoring device, whichis capable for measuring and monitoring the liquid level and liquid flowrate of the medical liquid in the IV bottle during whole infusionprocess, as well as for giving alarm when the medical liquid in the IVbottle drops to a predetermined low level. The present invention isdifferent from and superior over all the prior arts in function,structure, cost, accuracy and reliability, as well as ease of use.

SUMMARY OF THE INVENTION

An IV infusion monitoring device is provided to measure and to displaythe liquid level data including the weight of remaining medical liquidin an IV bottle, the liquid flow rate as number of drop per minuteduring infusion and the remaining time from the completion of the IVinfusion process etc. It also gives alarm as the medical liquid in theIV bottle drops to a predetermined low level. The monitoring devicesfurther combines with a server and at least one PDA devices (personaldigital assistant) to form a communication network for IV infusionmonitoring (i.e., network of things or interne of things for IV infusionmonitoring). A PDA device is a mobile device, e.g., a remote desk topcomputer in a nurse station, a laptop computer, or a palmtop computer.The liquid level data are transmitted from the monitoring device to theserver and then to the PDA devices through the communication network bywire or wirelessly. Therefore the nurses and other hospital workers canmonitor the IV infusion process in a remote device, e.g. a desktopcomputer in a nurse station or a palmtop computer carried by a nurse ora hospital worker etc.

An IV infusion system is used for injecting a medical liquid to apatient vein. It includes an IV bottle containing medical liquid inbottom and air above the medical liquid. Both a liquid needle for liquidflow and an air needle for air flow are inserted into the IV bottle. Aplastic liquid tube for liquid flow is connected at the end of theliquid needle. A plastic air tube for air flow is connected at the endof the air needle.

The preferred embodiment of the present invention comprises a loadsensor, a signal processor, a monitor terminal and a power. The loadsensor measures the gross weight of the IV bottle including the medicalliquid and the attachments e.g., the needles and the tubes. The measuredweight signal is then transmitted to the signal processor, which is ableto process the measured weight signal and obtain the liquid level dataincluding the weight of remaining medical liquid in an IV bottle, theliquid flow rate during infusion and the remaining time from thecompletion of the IV infusion process. The signal processor alsocompares the measured liquid level (e.g., the remaining weight of themedical liquid or the percentage of the remaining liquid weight over theinitial liquid weight in the IV bottle) to a predetermined value, andsends out an alarm signal to the monitor terminal as the measured liquidlevel is equal or less than the predetermined value. Meanwhile, all theliquid level data are sent from the signal processor to the monitorterminal for display during infusion process. The power is providedpreferably by a battery or a solar cell, alternatively by an externalpower source as an option to user.

The load sensor includes at least one strain gage. As a mechanical load(i.e., the gross weight of the IV bottle) is applied, the load is sensedby the strain gage, which outputs an electric signal, e.g., a voltage,in proportional to the applied mechanical load. The strain gage can bebonded or un-bonded, can be made of metal or semiconductor, can be madeof resistor or capacitor or inductor. To compensate the temperaturechange and obtain the best resolution, typically, at least one straingages and other electric parts (e.g., resistor, capacitor and inductor)form an electric bridge circuit consisting of 4 arms and 2 pair of ends,in which two ends receive an applied voltage while another two endsoutput the electric signal in proportional to the applied load on the atleast one strain gage.

The signal processor comprises (a) a signal amplifier, which is able toamplify the measured weight signal (e.g., a voltage) received from theload sensor, (b) an A/D converter, which converts the amplified weightsignal (e.g. an analog voltage) into a plurality of digital data, (c) amicroprocessor, which has software to analyze the plurality of digitaldata statistically and obtain the liquid level data. There is muchinterference electrically or mechanically during infusion process, forexample, as the patient moves or IV bottle is touched, the measuredsignal values vary. The microprocessor receives a plurality of digitaldata during infusion process including interference and noise. Thesoftware in the microprocessor is able to statistically analyze thesedata and filter out the interference and noises in order to obtainaccurate weight measurement of the medical liquid as a function of time.The liquid flow rate of the medical liquid in the IV bottle iscalculated as weight change per unit time, it can be converted intonumber of drop per unit time by using the estimated weight of each drop.The software is also capable for evaluating the initial weight of themedical liquid in the IV bottle. In addition, the software compares themeasured weight of remaining medical liquid in the IV bottle with thepredetermined value, and sends out an alarm signal as the measuredweight is equal or less than the predetermined value.

The monitor terminal comprises (a) a display mean which is able todisplay all liquid level data including the weight of remaining medicalliquid in the IV bottle, liquid flow rate and the time from thecompletion of the IV process, (b) an alarm means which gives alarm asthe monitor terminal receives an alarm signal from the signal processor,and (c) a data input means which receives data input and sends them tothe signal processor. The data input means includes manual input or theinput from the communication network. The display means includes aliquid-crystal screen on the monitor terminal. The alarm means includesa sound generator or a light generator.

There are two different monitoring modes, one is single monitoring mode,and another is network monitoring mode. In single monitoring mode, themonitoring is carried out in each monitoring device. In networkmonitoring mode, each set of liquid level data are transmitted throughthe communication network by wire or wirelessly from each monitoringdevice to a remote device, e.g., a desktop computer in a nurse station,a server or a palmtop computer carried by a nurse or a hospital workerin a remote location.

The alternative embodiment is a method to monitor the IV infusionprocess. The load sensor measures the gross weight Wg of the IV bottleincluding the medical liquid and the attachments, e.g., the needles andthe tubes as a function of time. The measured weight signal istransmitted to a signal amplifier for amplification. An A/D converterreceives the amplified signal from the signal amplifier and converts theanalog signal to a plurality of digital data, which are then passed to amicroprocessor for data analysis statistically to filter out allinterference and noise etc. The microprocessor then calculates theweight change ΔW as a function of time during infusion. Since all partshave fixed weight except the medical liquid during infusion, the weightchange must be the weight decrease of the medical liquid duringinfusion. The initial weight Wo of the medical liquid is evaluated atthe beginning of the infusion process by one of 3 different methods: (a)Evaluated by the software in microprocessor based the standard weightcategory of the medical liquid in the IV bottle; (b) Manual input frommonitor terminal, this is not preferred option since it increases thenurse's working load; (c) Input from the communication network. All theIV data from a doctor is inputted into the computer system including thepatient name, IV identification, the name and quantity of the medicineand solution etc. These IV data are stored in the computer system, andwill be transmitted into the microprocessor through the communicationnetwork. The weight of remaining medical liquid in the IV bottle iscalculated based on the difference between the initial weight of themedical liquid in the IV bottle and the weight change during infusion:Wr=Wo−ΔW. The percentage of the remaining medical liquid weight and theliquid flow rate are then respectively: Wr/Wo % and dW/dt. The remainingtime from completion of the infusion process is obtained by dividing Wrby dW/dt. These liquid level data are sent to the monitor terminal fordisplay in single monitoring mode, and are sent to the communicationnetwork in network monitoring mode so that a nurse or a hospital workercan monitor the infusion process from a remote location. Themicroprocessor also compares the weight of the remaining medical liquidto a predetermined value Wcritical, and sends an alarm signal to themonitor terminal to generate an alarm if the weight of the remainingmedical liquid is equal or less than the predetermined value: Wr.Meanwhile if the liquid flow rate is too low in comparison to apredetermined rate vale due to some accident during the infusionprocess, an alarm will also be generated to alert the nurses.

BRIEF DESCRIPTION OF THE DRΔWINGS

FIG. 1 is a schematic drawing of the installation of an IV infusionmonitoring device for the present invention.

FIG. 1A is a block diagram of an exemplary data label for the presentinvention.

FIG. 2 is the schematic drawing of an alternative installation method ofan IV infusion monitoring device for the present invention.

FIG. 3 is a block diagram of an exemplary IV infusion monitoring devicefor the present invention.

FIG. 4 is the schematic drawing of an exemplary electric bridge circuitof the load sensor in the present invention.

FIG. 5 is a block diagram of an exemplary signal processor for thepresent invention.

FIG. 5A is a block diagram of an exemplary microprocessor includingsoftware for the present invention.

FIG. 6 is a block diagram of an exemplary monitor terminal for thepresent invention.

FIG. 6A is a block diagram of an exemplary alarm means of the monitorterminal in the present invention.

FIG. 6B is a block diagram of an alternative alarm means of the monitorterminal in the present invention.

FIG. 7 is a flow chart of a monitoring method for the present invention.

FIG. 8 is a block diagram of a communication network by using themonitoring device.

FIG. 8A is a block diagram of an exemplary server in the presentinvention.

FIG. 8B is a block diagram of an exemplary PDA device in the presentinvention.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

In describing preferred embodiment of the present invention illustratedin the drawings, specific terminology is employed for the sake ofclarity. However, the invention is not intended to be limited to thespecific terminology so selected, and it is to be understood that eachspecific element includes all technical equivalents which operate in asimilar manner to accomplish a similar purpose.

FIG. 1 is a schematic drawing of the installation of an IV infusionmonitoring device 10 for the present invention that is capable ofdetecting the liquid level data including the weight of the remainingmedical liquid 11 in an IV bottle 12 or the ratio of the weight of theremaining medical liquid 11 over the initial weigh of the medical liquid11, liquid flow rate, and the remaining time from completion of IVprocess. It gives alarm when the weight of the remaining medical liquid11 in the IV bottle 12 drops to a predetermined low level. It also givesalarm if the IV infusion process encounters some trouble and results ina very slow liquid flow rate below a predetermined rate value.

An IV infusion system comprises the IV bottle 12, a liquid needle 14, anair needle 15, a liquid tube 16 and an air tube 17. The IV bottle 12contains the medical liquid 11 in its bottom and the air 13 above themedical liquid 11. The IV bottle 12 functions as a liquid supply sourceduring infusion. The IV bottle 12 can be made of stiff materials such asglass or harden plastics, or it can be made of flexible plastic bags.The liquid needle 14 and an air needle 15 are inserted into the IVbottle 12. The liquid tube 16 is connected at the end of the liquidneedle 14. The air tube 17 is connected at the end of the air needle 15.A data label 18 (FIG. 1A) including either of a magnetic stripe 18A,barcode label 18B or RFID tag 18C is disposed outside the IV bottle 12for containing all IV data including patient name, IV identification,the name and quantity of medicine and solution etc. The weight of themedical liquid 11 can be converted from weight unit (g) to volume unit(ml). The liquid flow rate can be converted from weight per unit timeinto the number of liquid drop per unit time based on estimated weightper drop.

Preferably, the IV infusion monitoring device is installed in an IV post19, which is fixed in a patient bed or seat, or stands alone next thepatient bed or seat.

FIG. 2 is the schematic drawing of an alternative installation method ofthe present invention. The IV infusion monitoring device 10 is installedin an IV bar 19A, which is fixed above the patient bed or seathorizontally. Alternatively, the IV infusion monitoring device 10 can beinstalled or held in any other position near the patient as long as theIV bottle 12 is relatively stable during infusion as well as it is abovethe patient to provide enough gravitational driving force for themedical liquid flow.

FIG. 3 is a block diagram of an exemplary IV infusion monitoring devicefor the present invention. The IV infusion monitoring device 10comprises a load sensor 20, a signal processor 21, a monitor terminal 22and a power 23. The load sensor 20 measures the gross weight of the IVbottle 12 including the medical liquid 11 and its attachments e.g., theneedles 14, 15 and the tubes 16, 17. The measured weight signal is thentransmitted to the signal processor 21, which is able to process thesignal and obtain the liquid level data including the weight of theremaining medical liquid 11 in the IV bottle 12 or the ratio of theweight of the remaining medical liquid 11 over the initial weigh of themedical liquid 11, liquid flow rate, and the remaining time fromcompletion of IV process. The signal processor 21 also compares themeasured weight of remaining medical liquid 11 to a predetermined value,and sends out an alarm signal to the monitor terminal 22 as the measuredweight of remaining medical liquid 11 is equal or less than thepredetermined value. All the liquid level data are sent from the signalprocessor 21 to the monitor terminal 22 by wire 27A for display duringinfusion process. The monitor terminal 22 gives an alarm in response tothe alarm signal from the signal processor 21. In addition, the monitorterminal 22 is capable of transmitting an input data to the signalprocessor 21 by wire 27. The power 23 is provided preferably by abattery 24 or a solar cell 25, alternatively by an external power source26 as an option to user. If the power is provided by a battery 24 or asolar cell 25, the negative pole of the battery 24 or solar cell 25 willact as a reference zero potential point, and therefore, all parts arenon-grounded and the monitoring device 10 becomes portable, i.e., it canmove around with a patient while in working condition.

FIG. 4 is the schematic drawing of an exemplary electric bridge circuit30 of the load sensor 20 in present invention. The load sensor 20includes at least one strain gage 31. As a load (i.e., the gross weightof the IV bottle) is applied, the load is sensed by the strain gage 31,which outputs an electric signal (i.e., measured weight signal), e.g., avoltage in proportional to the applied load. The strain gage 31 can bebonded or un-bonded, can be made of metal or semiconductor, and can bemade of resistor or capacitor or inductor. To compensate the temperaturechange and obtain the best resolution, typically, at least one straingages (e.g, one gage, two gages or four gages) and other electric parts(resistor, capacitor and inductor) 31, 31A, 31B and 31C form an electricbridge circuit 30 consisting of 4 arms 32, 32A, 32B, 32C and 2 pair ofends 33, 33A, 33B, 33C, in which two ends 33, 33B receive an appliedvoltage while another two ends 33A, 33C output the electric signal inproportional to the applied load on its at least one strain gage 31.

FIG. 5 is a block diagram of an exemplary signal processor 21 for thepresent invention. The signal processor 21 comprises a signal amplifier41, an A/D converter 42, a microprocessor 43, a data receiver 44 and adata transmitter 45. The signal amplifier 41 is able to amplify themeasured weight signal (e.g., a voltage) received from the load sensor20. The A/D converter 42 converts the amplified weight signal (e.g. ananalog voltage) into a group of digital data. The microprocessor 43contains software 46 (FIG. 5A) to analyze the digital data statisticallyand to obtain the liquid level data. The data receiver 44 receives inputdata from monitor terminal 22 by wire 27. The data transmitter 45 sendsout liquid level data to monitor terminal 22 by wire 27A. There is muchinterference electrically or mechanically during infusion process, forexample, as the patient moves or IV bottle 12 is touched, the measuredweight signal values vary. The microprocessor 43 receives a plurality ofdata during infusion process; these data also include interference andnoises. The software 46 in the microprocessor 43 is able tostatistically analyze these data to filter out the interference andnoises in order to obtain accurate weight measurement of the medicalliquid 11 in the IV bottle 12 as a function of time. The software 46 isalso capable for evaluating the initial weigh of the medical liquid 11in the IV bottle 12. The initial weight of the medical liquid 11 canalso be obtained alternatively from manual input in the monitor terminal22 or from a communication network 70 (FIG. 8). The liquid weight can beconverted from weight unit (g) to volume unit (ml) by using the liquidspecific weight. The liquid flow rate is calculated as weight change perunit time. However, the unit of the flow rate can be converted fromweight per unit time to number of drops per unit time by using estimatedweight per drop. The remaining time from the completion of IV process isobtained based on the remaining liquid weight and the liquid flow rate.In addition, the software 46 compares the measured weight of the medicalliquid 11 or the liquid flow rate to the predetermined values, and sendsout an alarm signal as the measured weight of the medical liquid 11 orliquid flow rate are equal or less than the predetermined weight valueor rate value respectively.

FIG. 6 is a block diagram of an exemplary monitor terminal 22 for thepresent invention. The monitor terminal 22 comprises a display mean 51,an alarm means 52 and a data input means 53. The display means 51 isable to display the liquid level data. The alarm means 52 gives alarm asthe monitor terminal 22 receives an alarm signal from the signalprocessor 21. The data input means 53 receives data input manually orfrom the communication network 70 (FIG. 8), and sends them to the signalprocessor 21. The monitor terminal 22 communicates with the signalprocessor 21 by wire 27, 27A. The display means 51 includes aliquid-crystal screen on the monitor terminal 22. The alarm means 52includes either a sound generator 56 (FIG. 6A) or a light generator 57(FIG. 6B).

FIG. 7 is a flow chart of a monitoring method for the present invention.Step 1 (61): The load sensor 20 measures the gross weight of the IVbottle 12 including the medical liquid 11 and the attachments, i.e., theneedles 14, 15 and the tubes 16, 17, and obtains a measured weightsignal. The measured weight signal is amplified by the signal amplifier41 to obtain an amplified weight signal. The amplified weight signal isfurther converted from an analog signal into a group of digital data,which are then analyzed statistically by the microprocessor 43 to obtainthe gross weight Wg of the IV bottle 12 including the medical liquid 11and the attachments 14, 15, 16, 17 as a function of time. Step 2 (62):The microprocessor 43 statistically analyzes the group of digital dataWg to filter out interference and noise, and calculates the weightchange ΔW of the IV bottle 12 including the medical liquid 11 and theattachments 14,15,16,17 as a function of time during infusion. Since allparts of the IV infusion system have fixed weight except the medicalliquid 11 during infusion, the calculated weight change must be theweight decrease ΔW of the medical liquid 11 during the infusion. Step 3(63): The initial weight Wo of the medical liquid 11 is evaluated at thebeginning of the infusion process by one of 3 different methods: (a)(63A) Evaluated by the software 46 in the microprocessor 43. The initialweight of the medical liquid 11 is not arbitrary, it is manufactured instandardized categories (e.g., 50 g, 100 g, 250 g, and 500 g etc., whichcan be converted into volume unit ml by liquid specific weight), and theweight of other parts are much smaller than the medical liquid 11.Therefore, it is not difficult for software 46 to determine whichinitial weight category the medical liquid 11 belongs to. For example,if the initial gross weight of the IV bottle 12 is measured to bebetween 260 g and 400 g, the initial weight of the medical liquid 11must be 250 g (or 250 ml in volume) after deducting the weight of IVbottle 12, needles 14, 15 and tubes 16, 17, it is the same for otherweight categories of 50 g, 100 g, 500 g, 1000 g etc.; (b) (63B) Manualinput from monitor terminal 22, this is not a preferred option since itincreases the nurse's working load; (c) (63C) Input throughcommunication network 70 from a remote device, e.g., a server 71 (FIG.8A) or a PDA device 72 (FIG. 8B). All the medical prescription data froma doctor is inputted into the computer system including IV data, e.g.,the patient name, IV identification, the name and quantity of themedicine and solution etc. These IV data are stored in the computersystem, and will be transmitted into the microprocessor 43 throughcommunication network 70, for example, the PDA device 72 including adata reader means 74 (one of a magnetic stripe reader 74A, a barcodescanner 74B or a RFID tag reader 74C) to read in the IV data from thedata label 18 and then transmit all the IV data to the server 71 andthen to the microprocessor 43. Step 4 (64): The weight of remainingmedical liquid 11 Wr in the IV bottle 12 at a given time is calculatedby the difference between the initial weight of the medical liquid 11 Woand the weight change ΔW at the given time during infusion: Wr=W0−ΔW.Step 5 (65): The percentage of the remaining medical liquid weight andthe liquid flow rate (weight change per unit time) are then obtainedrespectively: Wr/Wo % and dW/dt. Hereby, the liquid level is defined aseither Wr or Wr/Wo %. The remaining time from the completion of the IVinfusion process tr can also be calculated, e.g., dividing the remainingliquid weight Wr by the liquid flow rate dW/dt. The liquid level dataincluding the liquid level Wr or Wr/W0%, liquid flow rate dW/dt and theremaining time from IV completion tr. The unit of the weight can beconverted between g and ml by liquid specific weight, and the unit ofliquid flow rate can be converted between g/s and drop/s by liquidweight per drop. Step 6 (66): These liquid level data are sent to themonitor terminal 22 for display, or are sent to the communicationnetwork 70 for display in a remove device, e.g., a server 71 (FIG. 8A)or a PDA device 72 (FIG. 8B). Step 7 (67): The microprocessor 43 alsocompares the weight of the remaining medical liquid 11 to apredetermined value Wcritical (e.g., 10 g), and sends out an alarmsignal to the monitor terminal 22 or the communication network 70 togenerate alarm if the weight of the remaining medical liquid 11 is equalor less than the predetermined value: Wr≦Wcritical. Meanwhile, if anytrouble occurs during the IV infusion process, the liquid flow rate maybecome very low, then an alarm will also be generated to alert thenurses for treatment as the liquid flow rate drops below a predeterminedrate value. The above sequence of steps is applied for sake ofconvenience. Any change of the sequence also gives technical equivalentof the monitoring method, for example, the step 3 could move to beforestep 1, and it still gives the same method.

FIG. 8 is a block diagram of a communication network 70. There are twodifferent monitoring modes, one is single monitoring mode, and anotheris network monitoring mode. In single monitoring mode, the monitoringdevice 10 alone is applied for each patient, and the IV infusion processis monitored by using the monitoring device 10 only. In network mode, acommunication network for IV infusion monitoring 70 (i.e., internet ofthings or network of things for IV infusion monitoring) comprises atleast one monitoring device 10, 10A, 10B, a server 71 and at least onePDA device (personal digital assistant) 72, 72A, 72B, 72C. Eachmonitoring device 10, 10A, 10B is located next to each patient under IVinfusion process for measuring the liquid level data including theliquid level Wr or Wr/Wo %, the liquid flow rate dW/dt and the remainingtime tr from the completion of IV process. The server 71, as shown inFIG. 8A, typically a PC, includes display means 71A for displayingreceived liquid level data, as well as software 71B to analyze and tomanage data flow within the communication network 70. Each PDA device(i.e., personal digital assistant) 72, 72A, 72B, 72C, e.g., a remotedesk top computer in a nurse station, a laptop computer, a palmtopcomputer or other mobile devices, as shown in FIG. 8B, is carried by anurse or a hospital worker. Each PDA includes display means 73 fordisplaying received liquid level data and a data reader means 74, e.g.,a magnetic stripe reader 74A, a barcode scanner 74B or a RFID tag reader74C for scanning and reading in the IV data contained in the data label18 attached outside the IV bottle 12. The liquid level data aretransmitted from at least one monitoring device 10, 10A, 10B to theserver 71 by wire or wireless. The server 71 further sends all theliquid level data to each PDA device 72, 72A, 72B, 72C by wire orwireless. In reverse turn, the IV data including patient name, IVidentification, the name and quantity of medicine and solution etc. areread by the PDA device 72, 72A, 72B, 72C and they are then transmittedback to server 71 and further to each monitoring device 10, 10A, 10B.The server 71 is also capable to directly receive input data from theusers.

1. An IV infusion monitoring device, comprising: (a) a load sensorincluding at least one strain gage for measuring weight of medicalliquid in an IV bottle and for sending a measured weight signal to asignal processor, (b) said signal processor having signal amplifier foramplifying said measured weight signal and outputting an amplifiedweight signal, A/D converter for converting said amplified weight signalfrom analog signal to a group of digital data, microprocessor havingsoftware for statistically analyzing said a group of digital data andobtaining liquid level data, said liquid level data including weight ofremaining medical liquid in said IV bottle, liquid flow rate, andremaining time from completion of IV process, data transmitter fortransmitting said liquid level data to a monitor terminal, (c) saidmonitor terminal having display means for displaying said liquid leveldata, alarm means for give alarm as said weight of remaining medicalliquid drops to a predetermined value, (d) power supplier comprisingselected one of battery, solar cell and external power source forproviding power to said monitoring device.
 2. The monitoring device ofclaim 1, wherein said load sensor including an electric bridge circuitconsisting of 4 arms and 2 pair of ends, said at least one strain gagebeing installed in at least one arm, two ends of said electric bridgereceiving applied electric voltage while other 2 ends of said electricbridge outputting measured signal in proportional to applied weight loadon said at least one strain gage, said at least one strain gage beingmade of at least one of resistor, capacitor and inductor.
 3. Themonitoring device of claim 1, wherein said monitor terminal includingsaid alarm means for give alarm as said liquid flow rate drops to apredetermined rate value,
 4. The monitoring device of claims, whereinselected one of magnetic stripe, barcode label and RFID tag beingdisposed outside said IV bottle for providing IV data.
 5. The monitoringdevice of claim 1, wherein said monitoring device connecting to a serverand said server connecting to at least one PDA devices by selected oneof wire and wireless for forming a communication network, said serverincluding software for analyzing and managing data flow within saidcommunication network and display means for displaying said liquid leveldata, said at least one PDA devices including display means fordisplaying said liquid level data and data reader means includingselected one of magnetic stripe reader, barcode scanner and RFID tagreader for reading said IV data, said liquid level data beingtransmitted from said monitoring device to said server, and beingfurther transmitted to said at least one PDA devices, said IV data beingtransmitted back from said at least one PDA devices to said server andfurther to said monitoring device.
 6. A method of monitoring IV infusioncomprising: (a) evaluating initial weight Wo of medical liquid in an IVbottle by a microprocessor, (b) measuring gross weight of said IV bottleincluding said medical liquid and attachments by a load sensor, andobtaining a measured weight signal, amplifying said measured weightsignal by a signal amplifier, and obtaining an amplified weight signal,converting said amplified weight signal from an analog signal to a groupof digital data, analyzing statistically said a group of digital dataand obtaining said gross weight Wg as a function of time, (c)calculating weight change ΔW of said IV bottle including said medicalliquid and said attachments as a function of time by saidmicroprocessor, (d) calculating weight of remaining medical liquidWr=Wo−ΔW in said IV bottle as a function of time by said microprocessor,${\frac{Wr}{Wo}\mspace{14mu} \%},$ (e) calculating percentage of saidweight of remaining medical liquid (f) calculating liquid flow rate$\frac{W}{t}$ as weight per unit time, (g) calculating remaining timefrom completion of IV process tr, (h) displaying liquid level data, saidliquid level data including said weight of remaining medical liquid,said liquid flow rate, and said remaining time from completion of IVprocess, (g) giving alarm as said weight of remaining medical liquiddrops to a predetermined value.
 7. The method of claim 6, wherein saidliquid level data being transmitted to a server from a monitoring deviceby selected one of wire and wireless through a communication network,said liquid level data being further transmitted to a PDA device fromsaid server by selected one of wire and wireless through saidcommunication network.
 8. The method of claim 6, wherein selected one ofmagnetic stripe, barcode label and RFID tag being disposed outside saidIV bottle for containing IV data, said IV data including at least one ofpatient name, IV identification, name and quantity of medicine, as wellas name and quantity of solution, said IV data being read by selectedone of magnetic stripe reader, barcode scanner and RFID tag reader insaid PDA device, being transmitted from said PDA device to said sever,and being further transmitted to said monitoring device by selected oneof wire and wireless through said communication network.
 9. The methodof claim 6, wherein said initial weight Wo being inputted manually in amonitor terminal.
 10. The method of claim 6, wherein said initial weightWo being inputted through said communication network from said server.11. The method of claim 6, wherein said initial weight Wo being inputtedthrough said communication network from said PDA device by selected oneof magnetic stripe reader, barcode scanner and RFID tag reader.
 12. Themethod of claim 6, wherein said weight of medical liquid in said IVbottle being converted from unit of weight to unit of volume.
 13. Themethod of claim 6, wherein said liquid flow rate being converted intonumber of liquid drop per unit time based on estimated weight per drop.14. The method of claim 6, wherein said alarm being given as said liquidflow rate drops to a predetermined rate value.